Transcript Classification

Classification
Species of Organisms
•There are 13 billion known
species, but …
•Represents only 5% of all
organisms that ever lived!
•New organisms are still being
found and identified
What is Classification?
Classification is the
arrangement of organisms into
orderly groups based on their
similarities
Classification is also known as
taxonomy
Taxonomists are scientists that
identify & name organisms
Benefits of Classifying
•organisms
Accurately & uniformly names
•jellyfish
Prevents misnomers (starfish &
aren't really fish!)
•some
Uses same language (Latin or
Greek) for all names
Sea”horse”??
Confusion in Using Different
Languages for Names
Latin Names are Understood
by all Taxonomists
Early Taxonomists
•2000 years ago, Aristotle
was the first taxonomist
•He divided organisms
into plants & animals
•He subdivided them by
their habitat ---land,
sea, or air dwellers
Factors used to classify objects into a group are
called CRITICAL ATTRIBUTES.
Early Taxonomists
•John Ray, a
botanist, was the
first to use Latin
for naming
Names were very
long detailed
descriptions telling
everything about the
plant
•
Carolus Linnaeus
• 18th century
taxonomist
• Classified
•
organisms by
their structure
Developed
naming system
which is still
used today
Carolus Linnaeus
•Called the “Father of
Modern Taxonomy”
•Developed the modern
system of naming known as
binomial nomenclature
Two-word name (Genus &
species)
•
Standardized Naming
•Genus species
•Usually Latin
•Italicized in print
•Capitalize genus,
but NOT species
•Underline when
Turdus migratorius
writing
American Robin
Binomial Nomenclature
Corn
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Plantae
Spermatophyta
Magnoliophyta
Liliopsida
Cyperales
Poaceae
Zea (Genus)
mays (species)
Pioneer 32 D 99
Rules for Naming Organisms
• The International Code for
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Binomial Nomenclature contains
the rules for naming organisms
All names must be approved by
International Naming Congress
(International Zoological
Congress)
This prevents duplicated names
Classification Groups
• Taxon ( taxa-plural) is a
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category into which related
organisms are placed
There is a hierarchy of groups
(taxa) from broadest to most
specific
Domain, Kingdom, Phylum, Class,
Order, Family, Genus, species
Classification:
Day 2
Critical
attributes can
be used to
categorize
objects
What word do these have in common?
stick
hair
ball
man
wheel
high
pin
water
pen
soda
motion
poke
down
chair
back
light
short
fountain
steady
cart
slow
key
wall
precious
stop
cool
house
fat
go
slow
stone
stool
powder
ball
cat
foot
Domains
• Broadest, most inclusive taxon
• Three domains
• Archaea and Eubacteria are
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unicellular prokaryotes (no
nucleus or membrane-bound
organelles)
Eukarya are more complex and
have a nucleus and membranebound organelles
Archaea live in harsh environments and may
represent the first cells to have evolved.
Sewage
treatment
plants, thermal
vents, etc.
Eubacteria, some of which cause
human diseases, are present in
almost all habitats on earth.
Example:
E. coli live
in the
intestines
of animals
Many bacteria are important
environmentally and commercially.
Economic importance of bacteria
include
1) Medication – insulin
2) Food production – cheese,
sauerkraut
3) Forensics – increase suspect DNA
samples
Diseases caused by bacteria include
1) tuberculosis
2) meningitis
3) food poisoning (botulism)
4) strep throat (staphylococcus)
Domain Eukarya is Divided
into 4 Kingdoms
•Protista (protozoans, algae…)
•Fungi (mushrooms, yeast …)
•Plantae (multicellular plants)
•Animalia (multicellular animals)
Hierarchy of
Taxonomic Groups
BROADEST TAXON
Domain
Kingdom
Phylum (Division – used for plants)
Class
Order
Family
Genus
Species
King
Phillip
Came
Over
From
Great
Spain
Protista (protists)
•Most are
unicellular
•Some are
autotrophic
(plant-like),
while others are
heterotrophic
(animal-like)
ex: paramecia,
ameba, diatoms
•
Fungi
• Multicellular,
except yeast
• Absorptive
•
heterotrophs
(digest food
outside their
body & then
absorb it)
Cell walls
made of chitin
Plantae
•Multicellular
•Autotrophic
•Absorb
sunlight to
make glucose –
Photosynthesis
Cell walls
made of
cellulose
•
• Multicellular
• Ingestive
•
Animalia
heterotrophs
(consume food
& digest it
inside their
bodies)
Feed on plants
or animals
Taxon
•Each genus contains a number
of similar species, with the
exception of Homo which only
contains modern humans
(Homo sapiens)
Classification is based on
evolutionary relationships
•
Basis for Modern Taxonomy
•Homologous structures
(same structure, different
function)
Similar embryo development
Similarity in DNA, RNA, or
amino acid sequences
(proteins)
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Homologous Structures show similarities in mammals.
Similarities
in
Vertebrate
Embryos
Developing young are
immersed in an aquatic
environment whether in
an egg or a uterus, so
similarities exist.
Cladogram
Diagram showing how organisms are related
based on shared, derived characteristics such
as feathers, hair, or scales
Dichotomous Keys
•Used to identify organisms
•Characteristics given in
pairs
•Read both characteristics
and either go to another
set of characteristics OR
identify the organism
Example of Dichotomous Key
1a
1b
2a
2b
3a
3b
4a
4b
Tentacles present – Go to 2
Tentacles absent – Go to 3
Eight Tentacles – Octopus
More than 8 tentacles – 3
Tentacles hang down – go to 4
Tentacles upright–Sea Anemone
Balloon-shaped body–Jellyfish
Body NOT balloon-shaped - 5